To counteract the Allied maneuvers in Africa, the Italian Navy plans and raises an Algiers bay; the operation, identified by the code "NA 1", sees the joint action of SLC operators (slow-running torpedoes called "pigs") and "Gamma" men (assault swimmers), released in the roadstead by the approaching submarine Amber, started from La Spezia on December 4.
At the 21.45 the Italian boat is at the center of a semicircle around which six steamers are moored. From 5.00 to 7.00 the roadstead revives for multiple explosions: the naval raiders have sunk the merchant ships Ocean Vanquisher e Berto and severely damaged the steamers Empire Centaur e Harmattan for a total of over 22.000 tsl of ships.
